Universal DC input solutions for rail applications
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Universal DC input solutions for rail applications

Universal DC input solutions for rail applications


Providing an approved, single DC-DC power solution which covers all nominal traction voltages from 24VDC through to 110VDC and complies with the latest electromagnetic compatibility and fire protection standards, simplifies system integration across all power platforms that may be encountered in rail applications, negating the need for multiple variants of electronic transportation equipment.

With decades of experience providing power solutions for the rail industry and its demands on equipment to withstand the harsh climatic, mechanical and electrical environments encountered on traction vehicles and rolling stock thousands of XP Power products have been installed on rolling stock and trackside equipment globally.

Applications ranging from lighting, information & entertainment, safety and engine management systems to signalling, crossing control, in cabin radio and displays all require DC-DC power conversion and must perform safely and reliably.

The two main standards, detailing the input supply requirements for electronic equipment in rail applications, are EN50155:2017 and EN50121-2-1:2016. The table below outlines the continuous input voltage ranges along with the brown out and transient requirements of the nominal DC input supplies detailed in EN50155:2017. The same standard details the interruptions, surges, ESD and transient bursts that need to be considered as well as the environmental conditions such as temperature, humidity and shock and vibration.


Continuous Input Range, Brownout and Transient Requirements
Standard Nominal Input (Vnom) Specification
110 96 72 48 24
EN50155 77.0-137.5 V 67.2-120.0 V 50.5-90.0 V 33.6-60.0 V 16.6-30.0 V Continuous range
0.7-1.25 x Vnom
66.0 V 57.6 V 43.2 V 28.8 V 14.4 V Brownout 100ms
0.6 x Vnom
154.0 V 134.4 V 100.8 V 67.2 V 33.6 V Transient 1s 1.4 x Vnom


The continuous input voltage range of 16-160VDC and transient operation to 14VDC offered by the RDF series of 25 and 50W rail DC-DC converters covers all standard traction nominal battery voltages with the just one compact device. The units are compliant with EN45445-2 fire protection requirements, operate in ambient temperatures from -40 to 100degC and, with the addition of a minimum of external components comply with the latest electromagnetic compatibility standards.

The RDF25 comes in an industry standard 2”x1” PCB mount package with an option of an additional factory fitted heatsink to extend the temperature range for full power.


  • Regulated Single Output
  • Covers all nominal inputs from 24 to 110 VDC for Railway Applications
  • Wide 10:1 Input Range
  • 3000 VDC Isolation
  • High Efficiency
  • EN50155 Certified for Railway Applications
  • EN50121-3-2 with External Components
  • Remote On/Off
  • Output Voltage Trim ±10%
  • Operating Temperature -40 °C to +100 °C
  • Full Power to +55 °C
  • 3 Year Warranty

The RDF50 uses a standard ¼ brick baseplate cooled package allowing the full 50W of output power to be drawn at baseplate temperature to 100degC across the entire range of traction nominal battery supplies.


  • Ultra Wide 12:1 Input Range (14-160 VDC)
  • Single Output
  • Industry Standard 1/4 Brick
  • -40 °C to +100 °C Operation
  • 3000 VDC Isolation
  • Output Trim -20/+10%
  • Remote On/Off and Remote Sense
  • Complies with EN50155
  • Meets EN50121-3-2
  • 3 Year Warranty

Proven solutions based around these products are provided for EMC compliance with detailed reports from independent certified test laboratories to ensure easy integration into the end application regardless of the environmental & mechanical requirements of the final mounting location. These standard, off-the-shelf modules are either integrated directly into the end equipment or used as building blocks to provide complete centralized power solutions across all of the common traction power platforms with the low risk and fast time to market required in often project based system developments.

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